A web site is a group of related web pages that are available for retrieval via the Internet or another computer network. Parties that maintain web sites are sometimes called “publishers.” Some publishers sell to advertisers opportunities to include advertising messages on their web sites. For example, the publisher of a news web site may sell to an advertiser selling residential inspection services an opportunity to include advertisements on the publisher's web site.
In particular, publishers often sell opportunities to include advertising on particular pages of publishers' web sites having special significance. For example, because residential inspection services may be valuable to people who are in the market for a house, the publisher of the news web site may sell to the residential inspection services advertiser an opportunity to include advertisements on pages of the publisher's web site containing articles about real estate sales. As another example, the publisher may sell to the residential inspection services advertiser an opportunity to include advertisements on search result pages produced from user queries containing the search term “home sales.”
Another advertising paradigm used by publishers—referred to here as “targeted advertising”—involves selling opportunities to present advertising messages to particular groups of people, rather than selling opportunities to present advertising messages in particular places, such as on particular web pages. Targeted advertising is conventionally performed by having publishers include on some or all of the web pages of their web sites content, such as a pixel inclusion reference, that causes web browsers loading these web pages to contact a behavioral monitoring server, providing to the behavioral monitoring server both (1) a user identifier that was earlier stored on the user's computer system by the behavioral monitoring server and uniquely identifies the user or the user's computer system to the behavioral monitoring server, and (2) information identifying the particular web page loaded, and/or an action performed by the user with respect to the loaded web page. The unique user identifier is often needed because no other basis exists for uniquely identifying certain user computer systems, such as those who access the Internet through a proxy server that obscures the user computer system's source Internet Protocol address.
Each time the behavioral monitoring server is contacted, it is able to use the user identifier to unambiguously identify the client computer system in which the specified action was performed. Further, and more seriously, accumulating behavioral information about users who are uniquely associated with particular user identifiers in the manner described above, operators of behavioral monitoring servers may cause or permit this behavioral information to be linked with specific identifying information that discloses or suggests the identity of the user whose behavior it describes. The risk of such linking tends to make users resistant to submit to behavioral monitoring, which in turn makes it more difficult for advertisers to take advantage of targeted advertising and its significant benefits.
In view the foregoing, an approach to tracking user behavior in a manner that prevents that user behavior from being linked to information specifically identifying the user would have significant utility.